Ever been to Ireland mate?
As it happens, yes. Three years there.
Republican bombers are not motivated by religion, that's just the excuse. It's a political struggle and always has been. If you knew anything at all about the place, you would know that.
Middle America? Hardly. Lots of white, middle-class suicide bombers there, are there?
The other countries you mention, the motivation is ethnic, not religious.
No, Islam is the only religion that actively encourages it's followers to become martyrs while killing as many of those who are not of the same faith as possible. It is the only religion that has an explicit instruction in it's holy books to kill non-believers ("fight and slay the pagans (or infidels or unbelievers) wherever you find them" -Surah 9:5).
It's a big subject, certainly most Muslims are moderate and have no interest in killing anyone, however the faith provides a mechanism whereby extremists can justify their actions directly from their scriptures. No other religion does that. That is why it is so dangerous.